Synthesis and Biological Activities of Fused Phosphorus Heterocyclic Compounds(Ⅴ)
LU Rong-Jian, YANG Hua-Zheng, WANG Ling-Xiu
1996, 17(2):
236-240.
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The alkyl phosphorchloridisocyanatidate(2) is a kind of bifunctional compound which has a high reactivity.We have reported a new efficient method to prepare a new kind of fused phosphorus heterocyclic compounds using the reaction of the bifunctional compound─alkyl phosphorchloridisocyanatidate(2)with 5-amino-3-benzylthio-1,2,4-triazole and its analogues(1).In this paper,the cyclization reaction of aryl phosphonochloridisocyanatidate(2) with 5-amino-3-benzylthio-1,2,4-triazole and its analogues 1 was described. Twelve 2-benzylthio-7-aryl(alkoxyl)-7-phospha-5,7-dioxo-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5a]triazines were synthesized. The structures were assigned on the basis of 1H NMR,31P NMR,IRsupported by satisfactory elemental analysis.The 1H NMRspectrum of 2-benzylthio-7-phenyl-7-phospha-5,7-dioxo-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5a ]triazine(3c) shows doublet at δ8.72 with the coupling constant 2JPCH=8.9 Hz, single peak at δ10.84 for NHadjacent to the heterocyclic moiety.In NMRof 3c, one singlet at δ 4.2,appearing in the lower field than in that of 2-benzylthio-7-alkoxyl-7-phospha-5,7-dioxo-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5a]triazines(3a,3b,3c,3f,3i, 3j) which could be attributed to the deshielding effect of the phenyl substituent, indicated one isomer.The strong(C=O) stretching absorption band at 1681 cm-1 indicated that 3c existed in the keto form instead of enolic form.The most probable mechanism of the cyclization reaction was proposed.Initially nucleophilic addition of NH2 group to the isocyanate group of 2 gives an intermediate 4,which undergoes cyclization by nucleophilic attack of 1-NHgroup on Pwith the cleavage of P-Cl bond.The cyclization yield of aryl phosphonochloridisocyanatidate is lower than that of alkyl phosphorchloridisocyanatidate which might be due to the steric influence of the aryl group.On the basis of 1H NMR,32P NMR,IRspectra,Z-configuration could be proposed.The preliminary biological tests show that some compounds have herbicidal activities.
